Back-pressure valve



Aug. 17 1926. Q 1,596,260v

A. THOMSON I BACK PRESSURE VALVE Filed March 6, 1926 Patented Aug. 17, 1926.

PATENT orrlcs.

ALEXANDER THOMSON, F SOURLAK E, TEXAS.

BACK-PRESSURE VALVE.

Application filed March 6, 1926. Serial No. 92,947.

My invention relates to back pressure valves for use in oil well operations.

\Vhen an oil well has been drilled'to a sand whichis considered productive and a v 6 test thereof is desired, it is common to insert a well screen or perforatedprpe having thereon a back pressure valve, and-then -wash out the "well and test the supposed producing stratum. If the test is not satisfactory. and it is desired t6 drill deeper, it

frequently happens that the screen can not be removed as it becomes lodged or frozen in place. With the ordinary backpressure valve, it thenbecomes necessary to insert a and remove it in pieces. This is a difiicult andexpensive operation but there isfno alternative except the shooting or blasting of the screen and'valve so as to open. up aipassage for the drill thi'ough the stratum which has been tested. It is an object of my invention to construct a'back pressure valve and a set collar to accompany the same which may be attached to the lower end of the screen and permit the removal of the back pressure valve when it is desired. -It is also an objectto construct the back pressure valve so that the valve may. be positively opened dur ing the operation of washing the well inorder to test the formation in" which. thescreen is set. It is a further object to con struct the valve and its housing so that the sand and sediment may be washed clear from the valve when it is desired to-remove' it from the well. Invention resides par. ticularly in the construction and arrangement of the parts thereof, which will be illustrated in detail. hereafter. Referring to the drawing herewith, where'- in a preferred embodiment of the invention is disclosed, Fig. 1 is-a central longitudinal section through my improved back pressure valve-illustrating its connection to the low- 4 er'end of the strainer.

F ig. 3-is a transverse section on theplane 3-3 of Fig. 1. Like numerals of reference milling cutteror drill and cut up the-valve.

head portion 11 is shown in Fig. 2 is a side ele-. vation of the upper section of my valve.-

set collar. is connected? at its lower end by.

means of thecoupling 4 to the pipe or shoe 5 extending to the bottom of the well.

The'set shoe 3 is preferably threaded on its upper end, as shown at 6, with 'a leftvhand thread so that-its rotation in a right hand direction will only serve to tighten the 'collar withinthe coupling 2. The set collar is a tubular structure having the walls re cessed slightly between the ends, as shown at 8, thereby producing an inwardly projecting threaded portion 9 at the upper end and a-smooth inner side 10 at the lower end. ,The threaded portion 9 at the'upper end of the set collar is connected by means of a left-hand thread to the head 11 constituting lower end of the enlarged portion is beveled at 14 to provide a seatfor the nipple 15 .of the wash pipe.

The chamber within the upper threaded portion 13 is provided J with radial openings 16 connecting with the space 17 outside the head of the valve and v bet-ween the same and the lower wall of the screen 1. The lower end of the head His reduced in outer diameter andthreaded to receive the upper end 18 of the valve chamber. The general outer appearance of the i .2. The valve chamber. inclu ed within the ous1ng18, is'adapted to receive two sepa rate valves. end of the passage 12 through the head of the valvechamber is beveled at 19 to form.

a lower seat for a valve member 20. The

inwardly and. an upwardly tapered opening is formed therein to receiye a second valve n1ember22.

The uppervalye 20 is a hollow'member closed at its outer end and tapered at 23 to fitwithin the seat 19. It is held resiliently in position closing the passage 12.by means of a spring 24 hearing against the lower flangedportion 25 of the valve." The said For this purpose, the lower spring 24; bears at its lower end against a perforated disc 26 fitted within the lower end of. the valve chamber. The valve meme 20 includes an. inner chamber .27 open at its lower end provided with a plurality of lateral openings 28 connected with the interior of the valve chamber 18. i

The lower valve'22 has a tapered disc fitting within the seat 21 and has an upwardly extending guide rod 29. Said rod extends through a central opening in the disc 26 and has a nut and washer 30 at the upper end thereof which furnishes a bearing for a compression spring 31, which bears against the disc .26 at its lower endand tends to hold'the valve 22 resiliently upwardly within its seat.

In the use of this device the strainer 1 with the back pressure valve described will be'inserted into the well and set at the de sired position therein. The well will then be washed and in doing so awash pipe 32 will be inserted downwardly into the screen.

This wash pipe is formed with the nipple 15 v at its lower end reduced to. fit within the passage'12 and forming a nozzle therefor. The lower end of the nozzle is formed with curved notches 33 therein to allow'the passage of fluid more freely around its lower I opening.v It is contemplated that when the wash pipe is placed in position a tapered shoulder 34 thereon will contact with the seat 14 and close the-passage of water upwardly. The end of the wash pipe will contact with the valvemember 20 and depress it so that water may wash around the upper valve freely and downwardly through and past the valve 22 and through the pipe 5. into the lower end of the well, coming up outside the pipe and strainer tothe surface. When the well is thus washed, the wash pipe will be withdrawn and the well may then be tested.

. If it should happen that the back pressure valves, which I employ, do not appear to function properly, and. it becomes necess aryto withdraw them, or if the test proves unsuccessful and it is desired to remove the back pressurevalves a setting tool will'be inserted downwardly into the well, the lower 7 end being threaded to engage the threaded portion 13 of the head member of thevalve chamber. When the threaded tool has been screwed within the. seat 14, the continued rotation of the setting tool will rotate the head 11, as previously stated. -The connec tion of the head at 9 is a left-hand threaded connection, therefore, the rotation of the ,head 11 in a 'right-hand. direction will unscrew the valve from-the setting collar and r it will be freed therefrom and may be with- 'serted.

the pipe cut off, the fluid will pass through the openings 16 into the lower end of the screen and will wash upwardly therein carrying with it the sand lodged in the chamber or recess 17; When the sand is thus cleared from around the valve chamber, tlievalve may be readily removed. 7

If the valve needs adjustment, the adjustment m be made and the valveagain in- If, however, it is desired to drill deeper, a reamer may be inserted to cut away the set collar 3 or such portion thereof as is necessary to admit the passage of the drill bit, and the hole may then be deepened. It will be obvious that the removal of the valve chamber and the valves therein from the lower end of the screen will leave very little metal to be cut by the drill in order to allow its passage through the screen into thev stratum below for the purpose of deepening the hole. The. advantages of this construction will be apparent without further description.

What I claim as new and desire to protect by Letters Patent is: i

I 1. In a device of he character described, a set collar adapted t be secured to the lowerend of a pipe or screen, a valve casing head having a right-hand threadthereon for engagement with a setting tool, a valve casing secured to the lower end of said head and fitting slidably within the said collar, and. a downwardlyopeningvalve in said casing.

3'. In a device of the character described, a tubular set collar adaptedto be secured to a pipe or screen, a valve casing head having a left-hand threaded engagement within said collar, the upper end of said head extending above said collar and having an interior right-hand-threaded seat therein, said. seat having lateral openings therein, a valve cas- 1n" collar and downwardly opening valves in said casing.

4. In a de'vice'of the character described, a back pressure valve adapted to be attached at the lower end of a pipe or screen, said valve comprising a tubular head threaded on its outer face with a left-hand thread, avalve chamber below said head, and a downwardly opening valvein saidchamber.

5. A back pressure valve adapted to be below said head fitting slidably in said' connected by a left-hand threaded engagement at the lower end of a pipe or screen, said valve comprising a tubular headhaving a passage therethrough the upper end of which is enlarged and threaded in a righthand direction, a tapered shoulder at the lower end of said threaded end, avalve casing below said head, and a downwardly opening valve therein.

6. A back pressure valve adapted to be connected to a screen or pipe, said valve comprising a tubular head, the outer face of which is threaded in one direction for attachment to a supporting member, an inte- 'rior seat at the upper end threaded in the opposite direction, a valve casing below said head and removable therewith, and down- I Wardly opening valves in said casing.

' 7. A back pressure valve comprising an upper head member adapted for detachable engagement with a supporting pipe or screen,

a valve casing secured at the lower end of said head, a valve seat at the lower end of said head, a valveheld resiliently therein,

said valve comprising a hollow member closed at its upper end and open at its lower end, and having lateral openings therein for the purpose described.

8. A back pressure valve comprising an upper head member formed for detachable connection with a pipe or screen, said head having a central passage with valve seats at the upper and lower ends thereof, a valve casing at the lower end of said head member, a valve closing the lower end of said passage and a second valve closing the lower end of said casing.

In testimony whereof I hereunto afiix my signature this 27th day of February, A. D. 1926.

ALEXANDER THOMSON. 

